This invention relates generally to drainage systems for water or other liquids, and more particularly concerns a component for a trench drain system for capping the open ends of the trench drain channels.
Drainage systems which include trenches are used in numerous industrial and municipal applications where there is a need to drain a generally flat surface. For example, industrial settings sometimes require drainage systems formed in building floors to collect and remove excess water or other liquids. Outdoor industrial and commercial sites, such as airports, large parking lots, roadway medians, service station aprons, driveways and the like, require drainage systems to collect and direct rainwater and other liquids to prevent flooding and to decrease runoff.
Trench drain systems are usually constructed by placing and securing a number of premade channel sections in a ditch which has previously been formed in the ground. The channel sections are installed flush to grade or finish surface. Typically, the channel sections are precast from a material which is selected based upon the load requirements and the type of liquids which the system is designed to transport. The channel section can be formed of a variety of cementitious, polymeric or metal materials. In one type of trench drain system, the channel sections are formed of a combination of polymeric resin and aggregate material, referred to as polymer concrete.
The channel sections may be designed with a predetermined slope to facilitate fluid flow or with no slope. Each of the sloped channel sections has an upstream depth and downstream depth specific to that channel section. Channel sections having no slope are commonly referred to as neutral channels. Once the channel sections are positioned in the ditch, a cement-based material, usually concrete, is poured around the channel sections and allowed to set.
Drainage systems may be assembled in any number of configurations having turns, intersections and other transitions. The systems can also include a number of other components such as transition pieces, liquid collection basins, trash baskets, and the like, which are connected to the channel sections to provide drain run transitions, liquid collection points, and for the removal of solid debris. Since the various components of a drainage system can be spaced apart in the field, the system components are interconnected by pipes connected to outlets formed in the walls of the system components.
Another component of a trench drain system is an end cap. The end cap fits against the open end of the channel section. The inner wall surface of the end cap contacts the end of the channel section and is adapted to fit closely against the channel section end. A sealant can be used in the seam between the end cap and the end of the channel section to help prevent leakage.
There are two types of end caps: a terminal end cap and a drain end cap. The terminal end cap is a generally flat piece which is used to completely close off the open end of the channel section.
The drain end cap includes an outlet in which a short pipe extension is installed so that at least a portion of the pipe extension protrudes outwardly from the wall of the end cap for connection to a pipe. For example, a PVC pipe extension can be at least partially embedded or cast within a polymer concrete end cap during formation or molding of the end cap. Alternatively, the pipe extension can be installed in the end cap in the field, which requires that an appropriately-sized hole be formed in the end cap to receive at least a portion of the pipe extension. Pre-formed cut-outs in the end cap which must be drilled and chiseled out are sometimes provided for this purpose. The pipe extension is then secured in the hole with an adhesive. The drain end cap is used where pipe connections or other transitions are necessary, such as when bottom draining of the trench unit is not possible due to lack of available space. A pipe fitting, such as a coupler, is used to attach the pipe extension to the pipe.
A common problem with the use of trench drain systems is that many different size end caps are needed to accommodate varying channel section depths. This is particularly true when sloped channel sections are used since the depth of the channel section presented for capping will depend on the length of the trench drain run. Thus, the number of end caps which must be manufactured and sold are quite large, and the selection of the appropriately-sized end caps to match the channel section ends can be difficult.
Further, the use of drain end caps has been found to be a disadvantage for several reasons. In particular, manufacturing the drain end caps is problematic due to the difficulty of establishing a bond between the end cap and pipe extension, which is usually PVC. Because of the difficulty of getting a good chemical bond between the polyester resin and the PVC pipe, sometimes a groove is cut in the pipe extension prior to placing the piece in the mold and casting around the extension to help establish a mechanical bond.
If the pipe extension is installed in the field, a hole of relatively precise dimensions must be formed in the end cap in order to properly receive the pipe extension. Even where cut-outs are available, one must carefully drill and chisel the end cap to remove the cut-out. However, the materials which form the drainage system components are relatively brittle, especially as the percentage by weight of aggregate material increases. Thus, all or part of the end cap could shatter during formation of the hole.
Storage and transportation of the drain end caps can also be difficult and awkward since the pipe extension increases the fragility of the structure. During transportation and storage, the pipe extension can be bumped or otherwise impacted possibly fracturing the pipe extension, the end cap, or both.
Regardless of which installation method is used, a pipe fitting must generally be employed to secure the pipe to the outwardly extending portion of the pipe extension. Thus, use of the pipe extension to couple the end cap to the pipe increases the number of components required to assemble the drainage system and the resulting cost of the drainage system. Moreover, an additional joint is formed which may leak.
For the foregoing reasons, there is a need for an end cap component of a drainage system which can accommodate channel sections of different depths thereby reducing the number of end caps needed for a drainage system. Where a drain end cap is required, the end cap should include a pipe extension which is made so as to be nearly unbreakable. The pipe extension should be sized to serve as a standard pipe fitting thus eliminating the number of components necessary for assembling the drainage system. Preferably, the end cap would be easy to manufacture and install.